WO2024060787A1

WO2024060787A1 - Optical modulator and modulation method

Info

Publication number: WO2024060787A1
Application number: PCT/CN2023/105379
Authority: WO
Inventors: 董振; 简健; 张培杰; 刘辰钧; 桂成程
Original assignee: 华为技术有限公司
Priority date: 2022-09-22
Filing date: 2023-06-30
Publication date: 2024-03-28
Also published as: CN117784492A

Abstract

The present application is applied to the field of optical communications. Provided is an optical modulator. The optical modulator comprises a beam splitter, a first grounding electrode, a first waveguide, a first signal electrode, a second waveguide, a second signal electrode and a beam combiner. An output end of the beam splitter is connected to an input end of the first waveguide and an input end of the second waveguide. An input end of the beam combiner is connected to an output end of the first waveguide and an output end of the second waveguide. The first signal electrode is located between the first waveguide and the second waveguide. The first waveguide is located between the first grounding electrode and the first signal electrode. The second waveguide is located between the first signal electrode and the second signal electrode. By additionally providing signal electrodes, the voltage amplitude of modulation can be increased, thereby improving the modulation efficiency.

Description

Optical modulators and modulation methods

This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on September 22, 2022, with application number 202211170389.5 and the application name "Optical Modulator and Modulation Method", the entire content of which is incorporated into this application by reference. middle.

Technical field

The present application relates to the field of optical communications, and in particular to optical modulators and modulation methods.

Background technique

In the field of optical communications, optical sending equipment can convert electrical signals into optical signals through optical modulators. For example, the Mach-Zehnder modulator is the most commonly used optical modulator structure. The Mach-Zehnder modulator includes a beam splitter, a first ground electrode, a first waveguide, a signal electrode, a second waveguide, a second ground electrode and a beam combiner. The output end of the beam splitter is connected to the input ends of the first waveguide and the second waveguide. The input end of the beam combiner is connected to the output ends of the first waveguide and the second waveguide. The signal electrode is located between the first waveguide and the second waveguide. The first waveguide is located between the first ground electrode and the signal electrode. The second waveguide is located between the second ground electrode and the signal electrode. The signal electrode is used to connect one end of the differential electrical signal. The first ground electrode and the second ground electrode are used to connect the ground wire. In practical applications, the modulation efficiency of optical modulators is low.

Contents of the invention

This application provides an optical modulator and a modulation method. By adding signal electrodes, the modulation voltage amplitude can be increased, thereby improving the modulation efficiency.

A first aspect of this application provides an optical modulator. The optical modulator includes a beam splitter, a first ground electrode, a first waveguide, a first signal electrode, a second waveguide, a second signal electrode, and a beam combiner. The output end of the beam splitter is connected to the input ends of the first waveguide and the second waveguide. The beam splitter is used to split the received optical carrier into two optical carriers. The two optical carriers correspond to the two waveguides one-to-one. The first signal electrode is located between the first waveguide and the second waveguide. The first waveguide is located between the first ground electrode and the first signal electrode. The optical modulator modulates one of the two optical carriers through the first signal electrode and the first ground electrode to obtain a first optical phase modulation signal. The second waveguide is located between the first signal electrode and the second signal electrode. The optical modulator modulates the other of the two optical carriers through the first signal electrode and the second signal electrode to obtain a second optical phase modulation signal. The first signal electrode and the second signal electrode are respectively connected to an output port of the differential electrical signal. The first ground electrode is connected to ground or DC voltage. The input end of the beam combiner is connected to the output ends of the first waveguide and the second waveguide. The beam combiner is used to interfere with the first optical phase modulation signal and the second optical phase modulation signal, and output a modulated optical signal.

In an optional manner of the first aspect, the first ground electrode and the second signal electrode are symmetrically distributed with the first signal electrode as the center. When the first ground electrode and the second signal electrode are distributed asymmetrically, the optical losses of the two optical carriers may be different, resulting in poor quality of the modulated optical signal. Therefore, the present application can improve the quality of modulation.

In an optional manner of the first aspect, the light modulator further includes a second ground electrode. The second signal electrode is located on the second between the ground electrode and the second waveguide. By introducing the second ground electrode, the structure of the optical modulator can be made more symmetrical, thereby reducing the attenuation of high-frequency electrical signals on the electrode. Therefore, this application can reduce the loss of electrical signals, thereby increasing the modulation bandwidth.

In an optional manner of the first aspect, the second ground electrode and the first ground electrode are symmetrically distributed around the second waveguide. When the second ground electrode and the first ground electrode are symmetrically distributed, the attenuation of high-frequency electrical signals on the electrodes can be reduced. Therefore, this application can reduce the loss of electrical signals, thereby increasing the modulation bandwidth.

In an optional manner of the first aspect, the light modulator further includes a first dummy waveguide. The first dummy waveguide is located between the second ground electrode and the second signal electrode. By introducing a second false waveguide, the structure of the optical modulator can be made more symmetrical, thereby reducing the attenuation of high-frequency electrical signals on the electrodes. Therefore, this application can reduce the loss of electrical signals, thereby increasing the modulation bandwidth.

In an optional manner of the first aspect, the first waveguide and the first false waveguide are symmetrically distributed with the second waveguide as the center. When the first waveguide and the first pseudo waveguide are symmetrically distributed, the attenuation of high-frequency electrical signals on the electrodes can be reduced. Therefore, this application can reduce the loss of electrical signals, thereby increasing the modulation bandwidth.

In an optional manner of the first aspect, the light modulator further includes an electrical connection structure. The electrical connection structure is used to connect the second ground electrode and the first ground electrode. By connecting the second ground electrode and the first ground electrode, the introduced noise can be reduced. Therefore, this application can increase the modulation bandwidth.

In an optional manner of the first aspect, the electrical connection structure is a plurality of connection lines. The distance between any two adjacent connecting lines among the plurality of connecting lines is between 100 and 500 microns. By using multiple spaced connection lines, the noise on the electrodes can be reduced and the modulation bandwidth can be increased.

In an optional manner of the first aspect, the light modulator further includes a first resistor and a second resistor. The first resistor is connected to the output end of the first signal electrode. The second resistor is connected to the output end of the second signal electrode. By increasing the first resistor and the second resistor, the reflection of the electrical signal can be reduced, thereby improving the high-speed modulation performance of the optical modulator.

In an optional manner of the first aspect, the light modulator further includes a first capacitor and a second capacitor. The first capacitor is connected to the input end of the first signal electrode. The second capacitor is connected to the input terminal of the second signal electrode. The first resistor and the second resistor are connected to the DC bias voltage. By adjusting the DC bias voltage, the modulation operating point of the optical modulator can be adjusted. Therefore, this application can improve the flexibility of modulation.

In an optional manner of the first aspect, the first resistor and the second resistor are connected to the ground wire. A DC bias voltage is connected to the first ground electrode and the second ground electrode. By adjusting the DC bias voltage, the modulation operating point of the optical modulator can be adjusted. Therefore, this application can improve the flexibility of modulation.

In an optional manner of the first aspect, the light modulator has a U-shaped structure. The U-shaped structure includes a first straight portion, a curved portion and a second straight portion connected in sequence. In the first straight portion, the first waveguide is located between the first ground electrode and the first signal electrode, and the second waveguide is located between the first signal electrode and the second signal electrode. In the second straight portion, the first waveguide is located between the first signal electrode and the second signal electrode, and the second waveguide is located between the second signal electrode and the second ground electrode. At this time, the first waveguide and the second waveguide do not need to cross at the curved portion. Crossed waveguides will cause the two optical phase modulation signals to interact with each other and reduce the modulation quality. Therefore, the present application can improve the modulation quality.

In an alternative to the first aspect, the light modulator further includes a second dummy waveguide. In the second straight portion, the second dummy waveguide is located between the first ground electrode and the first signal electrode. By introducing the second false waveguide, the structure of the optical modulator in the second linear part can be made more symmetrical, thereby increasing the modulation bandwidth. Moreover, the second false waveguide will not intersect with the first waveguide and the second waveguide, thereby improving the modulation quality.

A second aspect of this application provides an optical module. The optical module includes a laser and the aforementioned first aspect or any one of the first aspects. Means an optical modulator described in an optional manner. The laser is used to output an optical carrier wave to the optical modulator. The optical modulator is used to modulate the optical carrier and output the modulated optical signal.

The third aspect of this application provides an optical sending device. The optical sending device includes a processor and the optical module described in the second aspect. The processor is used to output differential electrical signals to the optical module. The optical module is used to modulate the optical carrier according to the differential electrical signal and output the modulated optical signal.

A fourth aspect of this application provides an optical communication system. The optical communication system includes an optical receiving device and the optical transmitting device described in the third aspect. The optical sending device is used to send modulated optical signals to the optical receiving device. The optical receiving device is used to demodulate the modulated optical signal to obtain an electrical signal.

The fifth aspect of this application provides a modulation method. The modulation method can be applied to optical transmitting equipment. The modulation method includes the following steps: the optical sending device modulates the phase of the first optical carrier through an electrical signal in the differential electrical signal to obtain a first optical phase modulation signal. The optical sending device modulates the phase of the second optical carrier using the two electrical signals in the differential electrical signal to obtain a second optical phase modulation signal. The optical sending device interferes with the first optical phase modulation signal and the second optical phase modulation signal to obtain a modulated optical signal.

Description of drawings

Figure 1 is a first structural schematic diagram of an optical modulator provided by an embodiment of the present application;

Figure 2 is a second structural schematic diagram of an optical modulator provided by an embodiment of the present application;

Figure 3a is a third structural schematic diagram of an optical modulator provided by an embodiment of the present application;

Figure 3b is a first cross-sectional schematic diagram of the optical modulator provided by the embodiment of the present application;

Figure 3c is a second cross-sectional schematic diagram of the optical modulator provided by the embodiment of the present application;

FIG3 d is a third cross-sectional schematic diagram of the light modulator provided in an embodiment of the present application;

FIG3e is a fourth cross-sectional schematic diagram of the light modulator provided in an embodiment of the present application;

FIG4 is a fourth structural schematic diagram of an optical modulator provided in an embodiment of the present application;

Figure 5 is a fifth structural schematic diagram of an optical modulator provided by an embodiment of the present application;

Figure 6 is a sixth structural schematic diagram of an optical modulator provided by an embodiment of the present application;

Figure 7 is a seventh structural schematic diagram of an optical modulator provided by an embodiment of the present application;

Figure 8 is an eighth structural schematic diagram of an optical modulator provided by an embodiment of the present application;

Figure 9 is a schematic structural diagram of an optical module provided by an embodiment of the present application;

FIG10 is a schematic diagram of the structure of an optical transmission device provided in an embodiment of the present application;

Figure 11 is a schematic structural diagram of an optical communication system provided by an embodiment of the present application;

FIG. 12 is a flow chart of the modulation method provided in an embodiment of the present application.

Detailed ways

This application provides an optical modulator and a modulation method. By adding signal electrodes, the modulation voltage amplitude can be increased, thereby improving the modulation efficiency. It should be understood that the terms "first", "second", etc. used in this application are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. In addition, reference numbers and/or letters are repeated in the various drawings of this application for the sake of conciseness and clarity. Repetition does not imply a strictly limiting relationship between the various embodiments and/or configurations.

The optical modulator provided by this application is used in the field of optical communications. In the field of optical communications, optical sending equipment can convert electrical signals into optical signals through optical modulators. Specifically, the optical modulator modulates the optical carrier through one electrical signal of the differential electrical signal to obtain a modulated optical signal. However, the other end of the differential electrical signal is cut off, resulting in a waste of the driving signal, resulting in low modulation efficiency of the optical modulator.

To this end, this application provides an optical modulator. Figure 1 is a first structural schematic diagram of an optical modulator provided by an embodiment of the present application. As shown in FIG. 1 , the optical modulator 100 includes a beam splitter 101 , a first waveguide 102 , a second waveguide 103 , a beam combiner 104 , a first ground electrode 105 , a first signal electrode 106 and a second signal electrode 107 . The output end of the beam splitter 101 is connected to the input ends of the first waveguide 102 and the second waveguide 103 . The beam splitter 101 is used to divide the received optical carrier into two optical carriers. The two optical carriers correspond to the two waveguides one-to-one. The two waveguides include a first waveguide 102 and a second waveguide 103 . The first waveguide 102 may also be called an upper waveguide. The second waveguide 103 may also be called a lower waveguide. The first signal electrode 106 is located between the first waveguide 102 and the second waveguide 103 . The first waveguide 102 is located between the first ground electrode 105 and the first signal electrode 106 . The optical modulator 100 modulates one of the two optical carriers through the first ground electrode 105 and the first signal electrode 106 to obtain a first optical phase modulation signal. The second waveguide 103 is located between the first signal electrode 106 and the second signal electrode 107 . The optical modulator 100 modulates the other of the two optical carriers through the first signal electrode 106 and the second signal electrode 107 to obtain a second optical phase modulation signal. The first signal electrode 106 and the second signal electrode 107 are respectively connected to an output port of a differential electrical signal. The first ground electrode 105 is connected to ground or DC voltage. The input end of the beam combiner 104 is connected to the output ends of the first waveguide 102 and the second waveguide 103 . The beam combiner 104 is used to interfere with the first optical phase modulation signal and the second optical phase modulation signal, and output a modulated optical signal.

Define the output amplitude of the differential electrical signal as 2A, that is, the amplitude of the single-ended electrical signal is A. At this time, the driving voltage of the first waveguide 102 is A. The driving voltage of the second waveguide 103 is 2A. The overall driving voltage of the optical modulator 100 is 3A. Therefore, by adding signal electrodes, the voltage amplitude of modulation can be increased, thereby improving modulation efficiency.

The distance between the first ground electrode 105 and the first signal electrode 106 is defined as d1. The distance between the first signal electrode 106 and the second signal electrode 107 is defined as d2. In practical applications, d1 and d2 will affect the optical loss of the two optical carriers. When the optical losses of the two optical carriers are different, the quality of the modulated optical signal will be affected. In order to improve the quality of modulation, the first ground electrode 105 and the second signal electrode 107 may be symmetrically distributed with the first signal electrode 106 as the center. Among them, symmetrical distribution means that the difference between d1 and d2 is less than 5 microns. Similarly, in the following example, when A and B are described as being symmetrically distributed with C as the center, the difference between the distance between A and C and the distance between B and C is less than 5 microns.

It should be understood that the first ground electrode 105 and the first signal electrode 106 may not be completely parallel. The distance between the first ground electrode 105 and the first signal electrode 106 may be different at different locations. At this time, d1 refers to the average distance between the first ground electrode 105 and the first signal electrode 106 . Similarly, when the first ground electrode 105 and the first signal electrode 106 are not completely parallel, d2 refers to the average distance between the first signal electrode 106 and the second signal electrode 107 .

In practical applications, when the structure of the optical modulator 100 is asymmetric, the attenuation of high-frequency signals on the electrodes may be increased, thereby increasing the loss of electrical signals. To this end, the light modulator 100 in the embodiment of the present application may further include a second ground electrode. Figure 2 is a second structural schematic diagram of an optical modulator provided by an embodiment of the present application. As shown in FIG. 2 , based on FIG. 1 , the light modulator 100 further includes a second ground electrode 201 . The second signal electrode 107 is located between the second ground electrode 201 and the second waveguide 103 . The second ground electrode 201 is connected to a ground wire or a DC voltage. By introducing the second ground electrode 201, the structure of the optical modulator 100 can be made more symmetrical, thereby reducing the loss of electrical signals. It should be understood that for the sake of simplicity of the drawing, some of the existing reference numerals in Figure 1 are omitted in Figure 2 . Similarly, in subsequent examples, the referenced figures may omit some of the existing reference numerals in the cited figures.

In order to further improve the symmetry of the optical modulator 100, the optical modulator 100 in the embodiment of the present application may further include a first pseudo waveguide. Figure 3a is a third structural schematic diagram of an optical modulator provided by an embodiment of the present application. As shown in Figure 3a, based on Figure 2, the optical modulator 100 also includes a first dummy waveguide 301. The first dummy waveguide 301 is located between the second ground electrode 201 and the second signal electrode 107 . The first dummy waveguide 301 does not need to transmit optical carrier waves. By introducing the first dummy waveguide 301, the structure of the optical modulator 100 can be made more symmetrical, thereby reducing the loss of electrical signals.

By improving the symmetry of the optical modulator 100, it is beneficial to reduce the loss of electrical signals and increase the modulation bandwidth. To this end, in embodiments, the second ground electrode 201 and the first ground electrode 105 may be symmetrically distributed with the second waveguide 103 as the center, and/or the first waveguide 102 and the first pseudo waveguide 301 may be centered with the second waveguide 103 It is distributed centrally symmetrically.

In this embodiment of the present application, the first waveguide 102 and the second waveguide 103 may be strip optical waveguides or ridge optical waveguides. These are described separately below.

Figure 3b is a first cross-sectional schematic diagram of the optical modulator provided by the embodiment of the present application. Figure 3b is a cross-section along the dotted line 302 of Figure 3a. As shown in Figure 3b, the light modulator 100 includes 3 waveguides and 4 electrodes. The 4 electrodes include the first ground electrode 105, the first signal electrode 106, the second signal electrode 107 and the second ground electrode 201. The 3 waveguides include the first waveguide 102, the second waveguide 103 and the first dummy waveguide 301. 3 The waveguides are all strip optical waveguides. The light modulator 100 can also be filled with silicon dioxide SiO ₂ 303 or other dielectric layer materials in the vacant places.

Figure 3c is a second cross-sectional schematic diagram of the optical modulator provided by the embodiment of the present application. Figure 3c is a cross-section along the dotted line 302 of Figure 3a. As shown in Figure 3c, the light modulator 100 includes a waveguide 304 and four electrodes. The four electrodes include a first ground electrode 105, a first signal electrode 106, a second signal electrode 107 and a second ground electrode 201. Waveguide 304 is a ridge optical waveguide. The waveguide 304 includes three raised waveguides. The three raised waveguides include the first waveguide 102, the second waveguide 103 and the first dummy waveguide 301.

In Figures 3b and 3c, the waveguide and electrodes are in the same layer. In practical applications, waveguides and electrodes can be in different layers. Figure 3d is a third schematic cross-sectional view of the optical modulator provided by the embodiment of the present application. On the basis of Figure 3b, by moving down three waveguides, the optical modulator 100 shown in Figure 3d can be obtained. At this time, the 3 waveguides and 4 electrodes are in different layers. Figure 3e is a fourth schematic cross-sectional view of the optical modulator provided by the embodiment of the present application. On the basis of Figure 3c, by moving the waveguide 304 downward, the optical modulator 100 shown in Figure 3e can be obtained. At this time, the waveguide 304 and the four electrodes are in different layers. The three protruding waveguides on the waveguide 304 are also on different layers from the four electrodes.

In practical applications, the first ground electrode 105 and the second ground electrode 201 may introduce noise. Noise affects the quality of modulation. To this end, in the embodiment of the present application, the optical modulator 100 may further include an electrical connection structure. The electrical connection structure is used to connect the second ground electrode 201 and the first ground electrode 105 . Figure 4 is a fourth structural schematic diagram of an optical modulator provided by an embodiment of the present application. As shown in Figure 4, based on Figure 3a, the optical modulator 100 further includes an electrical connection structure 401. The electrical connection structure 401 is a plurality of connection lines. Two ends of each of the plurality of connection lines are connected to the first ground electrode 105 and the second ground electrode 201 respectively. The distance between any two adjacent connecting lines among the plurality of connecting lines is between 100 and 500 microns. By connecting the second ground electrode 201 and the first ground electrode 105, the introduced noise can be reduced. Therefore, the embodiments of the present application can increase the modulation bandwidth.

According to the foregoing description of FIG. 1 , it can be known that the input end of the first signal electrode 106 is used to connect an output port of a differential electrical signal. The input end of the second signal electrode 107 is used to connect to another output port of the differential electrical signal. In practical applications, the electrical signal may be reflected from the output end of the signal electrode back to the signal electrode, thereby affecting the high-speed modulation performance of the optical modulator 100 . To this end, in the embodiment of the present application, the optical modulator 100 may further include a first resistor and a second resistor. Figure 5 is a fifth structural schematic diagram of an optical modulator provided by an embodiment of the present application. As shown in Figure 5, on the basis of Figure 3a, the optical modulator 100 also It includes a first resistor 501 and a second resistor 502. The first resistor 501 is connected to the output end of the first signal electrode 106 . The second resistor 502 is connected to the output end of the second signal electrode 107 . The first resistor 501 and the second resistor 502 may also be called cut-off resistors or termination resistors (TR). By adding the first resistor 501 and the second resistor 502, the reflection of the electrical signal can be reduced, thereby improving the high-speed modulation performance of the optical modulator 100.

According to the aforementioned description of FIG. 5 , one end of the first resistor 501 is connected to the output end of the first signal electrode 106 . One end of the second resistor 502 is connected to the output end of the second signal electrode 107 . In practical applications, the other ends of the first resistor 501 and/or the second resistor 502 may be connected to different locations, which will be described respectively below.

In the first example, the other ends of the first resistor 501 and the second resistor 502 are respectively grounded, or the other ends of the first resistor 501 and the second resistor 502 are connected in parallel and then grounded. In the second example, the other end of the first resistor 501 is connected to the other end of the second resistor 502 . In the third example, the other end of the first resistor 501 is connected to the first ground electrode 105 . The other end of the second resistor 502 is connected to the second ground electrode 201 .

In practical applications, in order to improve modulation flexibility, the optical modulator 100 can also be connected to a DC bias voltage. By adjusting the DC bias voltage, the modulation operating point of the optical modulator 100 can be adjusted. Two possible implementation methods are described below.

Figure 6 is a sixth structural schematic diagram of an optical modulator provided by an embodiment of the present application. As shown in FIG. 6 , based on FIG. 5 , the optical modulator 100 further includes a first capacitor 601 and a second capacitor 602 . One end of the first capacitor 601 is connected to one end of the differential electrical signal. The other end of the first capacitor 601 is connected to the input end of the first signal electrode 106 . One end of the second capacitor 602 is connected to the other end of the differential electrical signal. The other end of the second capacitor 602 is connected to the input end of the second signal electrode 107 . The output end of the first signal electrode 106 is connected to the first resistor 501 . The output end of the second signal electrode 107 is connected to the second resistor 502 . The first resistor 501 and the second resistor 502 are connected to the DC bias voltage. The first capacitor 601 and the second capacitor 602 are used to isolate the DC bias voltage.

Figure 7 is a seventh structural schematic diagram of an optical modulator provided by an embodiment of the present application. As shown in FIG. 7 , based on FIG. 5 , the first ground electrode 105 and the second ground electrode 201 are connected with a DC bias voltage. One end of the first resistor 501 is connected to the output end of the first signal electrode 106 . The other end of the first resistor 501 is connected to the ground wire. One end of the second resistor 502 is connected to the output end of the second signal electrode 107 . The other end of the first resistor 501 is connected to the ground wire.

In practical applications, in order to reduce the length of the optical modulator, the optical modulator can have a U-shaped structure. FIG. 8 is an eighth structural schematic diagram of an optical modulator provided by an embodiment of the present application. As shown in Figure 8, the optical modulator 100 has a U-shaped structure. The U-shaped structure includes a straight part and a curved part. The curved portion refers to the portion of the light modulator 100 to the right of the dotted line 801. The straight line part refers to the part of the light modulator 100 to the left of the dotted line 801. The straight line portion includes a first straight line portion and a second straight line portion. The first straight line portion refers to the portion of the straight line portion above the dotted line 802. The second straight line portion refers to the straight line portion downward from the dotted line 802 . The three parts of the optical modulator 100 are described respectively below.

In the first linear section, the light modulator 100 includes 3 waveguides and 4 electrodes. The four electrodes include the first ground electrode 105, the first signal electrode 106, the second signal electrode 107 and the second ground electrode 201 in the direction from top to bottom. The three waveguides include the first ground electrode 105 in the direction from top to bottom. Waveguide 102, second waveguide 103 and first dummy waveguide 301. The first waveguide 102 is between the first ground electrode 105 and the first signal electrode 106 . The second waveguide 103 is between the first signal electrode 106 and the second signal electrode 107 . The first dummy waveguide 301 is between the second signal electrode 107 and the second ground electrode 201 . Regarding the description of the first straight line portion, reference may be made to the aforementioned description of FIG. 3a.

In the curved portion, the light modulator 100 includes 2 waveguides and 4 electrodes. The four electrodes include the second ground electrode 201, the second signal electrode 107, the first signal electrode 106 and the first ground electrode 105 from the inside to the outside along the center 803. 2 The waveguides include the second waveguide 103 and the first waveguide 102 in order from the inside to the outside along the center 803. To avoid waveguides and electrodes crossing, the waveguides and electrodes can be in different layers.

In the second straight section, the light modulator 100 includes 3 waveguides and 4 electrodes. The four electrodes are the second ground electrode 201, the second signal electrode 107, the first signal electrode 106 and the first ground electrode 105 in the direction from top to bottom. The three waveguides are the second ground electrode in the direction from top to bottom. Waveguide 103, first waveguide 102 and second dummy waveguide 804. The second waveguide 103 is between the second ground electrode 201 and the second signal electrode 107 . The first waveguide 102 is between the second signal electrode 107 and the first signal electrode 106 . The second dummy waveguide 804 is between the first signal electrode 106 and the first ground electrode 105 . The second dummy waveguide 804 does not need to transmit an optical carrier. For descriptions of the output terminals of the first signal electrode 106, the second signal electrode 107, the first ground electrode 105, and the second ground electrode 201, reference may be made to the description in any of FIGS. 4 to 7. For example, the output end of the first signal electrode 106 is connected to a first resistor. The output end of the second signal electrode 107 is connected to the second resistor.

In practical applications, intersecting waveguides will cause the two optical phase modulation signals to affect each other, thereby reducing the modulation quality. In FIG. 8 , the first waveguide 102 and the second waveguide 103 of the optical modulator 100 may not need to cross each other. Therefore, the embodiments of the present application can improve the modulation quality. Moreover, by introducing the second dummy waveguide 804, the symmetry of the second straight line portion can be improved, thereby reducing the loss of the electrical signal.

It should be understood that FIGS. 1 to 8 are just multiple examples of the optical modulator 100 provided by embodiments of the present application. In practical applications, those skilled in the art can make adaptive modifications to the structure of the optical modulator 100 according to requirements. For example, in FIGS. 5 and 6 , the light modulator 100 may not include the second ground electrode 201 and the first dummy waveguide 301 . As another example, in Figure 7, the optical modulator 100 also includes an electrical connection structure. The electrical connection structure is used to connect the first ground electrode 105 and the second ground electrode 201 . For another example, the optical modulator 100 in FIG. 8 does not include the first ground electrode 105 and the second dummy waveguide 804 in the second straight portion.

The optical modulator provided by the embodiment of the present application is described above. The following describes the optical module, optical sending device, and optical communication system provided by the embodiments of the present application.

Figure 9 is a schematic structural diagram of an optical module provided by an embodiment of the present application. As shown in FIG. 9 , the optical module 900 includes a laser 901 and an optical modulator 100 . The laser 901 is used to output an optical carrier wave to the optical modulator 100 . The optical modulator 100 is used to modulate an optical carrier wave and output a modulated optical signal. Regarding the description of the optical modulator 100, reference may be made to the description in any of the aforementioned figures in FIGS. 1-8. For example, light modulator 100 includes beam splitter 101 . The optical modulator 100 splits the optical carrier into two optical carriers through the beam splitter 101 . The optical modulator 100 modulates the phase of the first optical carrier using one of the differential electrical signals to obtain a first optical phase modulation signal. The optical modulator 100 modulates the phase of the second optical carrier using the two electrical signals in the differential electrical signal to obtain a second optical phase modulation signal. The optical modulator 100 interferes with the first optical phase modulation signal and the second optical phase modulation signal through the beam combiner 104 to obtain a modulated optical signal.

Figure 10 is a schematic structural diagram of an optical sending device provided by an embodiment of the present application. As shown in Figure 10, the optical sending device 1000 includes a processor 1001 and an optical module 900. The processor 1001 may be a central processing unit (CPU), a network processor (NP), or a combination of CPU and NP. The processor 1001 may also be a graphics processor (graphic processing unit, GPU). The processor 1001 may further include a hardware chip or other general-purpose processor. The above-mentioned hardware chip can be an application specific integrated circuit (ASIC), a programmable logic device (PLD) or a combination thereof. The processor 1001 is used to output differential electrical signals to the optical module 900 . The optical module 900 is used to modulate the optical carrier according to the differential electrical signal and output the modulated optical signal. For description of the optical module 900, reference may be made to the description of FIG. 9 .

In practical applications, the optical transmitting device 1000 may also include a memory. The memory may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Among them, non-volatile memory can be read-only memory Memory (read-only memory, ROM), programmable read-only memory (programmable ROM, PROM), erasable programmable read-only memory (erasable PROM, EPROM), or flash memory, etc. Volatile memory may be random access memory (RAM). The memory is connected to the processor 1001. Data may be stored in the memory. The processor 1001 can be used to obtain data from the memory and obtain differential electrical signals based on the data.

In practical applications, the optical sending device 1000 may also include a photodetector, a transimpedance amplifier or a driver (Driver, DRV), etc. The photodetector is used to receive optical signals and convert the optical signals into electrical signals. The transimpedance amplifier is used to convert the current signal output by the photodetector into a voltage signal and amplify the signal amplitude. The driver is used to receive a differential electrical signal from the processor, amplify the signal amplitude of the differential electrical signal, and output the amplified differential electrical signal through two output ports. The optical modulator is connected to the driver. Specifically, the first signal electrode and the second signal electrode in the light modulator are respectively connected to one of the two output ports.

Figure 11 is a schematic structural diagram of an optical communication system provided by an embodiment of the present application. As shown in FIG. 11 , an optical communication system 1100 includes an optical receiving device 1101 and an optical transmitting device 1000 . The optical sending device 1000 is used to send the modulated optical signal to the optical receiving device 1101. For description of the optical transmitting device 1000, reference may be made to the description of FIG. 10 . The optical receiving device 1101 is used to demodulate the modulated optical signal to obtain an electrical signal. It should be understood that the optical receiving device 1101 can also modulate the optical carrier according to the differential electrical signal to obtain a modulated optical signal. Therefore, regarding the description of the light receiving device 1101, reference may also be made to the description of the light transmitting device 1000.

Figure 12 is a schematic flowchart of a modulation method provided by an embodiment of the present application. The modulation method can be applied to optical modulators, optical modules or optical transmitting equipment. The following uses an optical modulator as an example to describe the modulation method. The modulation method includes the following steps.

In step 1201, the optical modulator modulates the phase of the first optical carrier using one of the differential electrical signals to obtain a first optical phase modulation signal.

Regarding the description of the optical modulator, reference may be made to the description in any of Figures 1 to 8. For example, the light modulator includes a first ground electrode and a first signal electrode. A first waveguide is included between the first ground electrode and the first signal electrode. The first waveguide is used to transmit the first optical carrier. The first signal electrode is used to connect one end of the differential electrical signal. The modulator modulates one of the two optical carriers through the first ground electrode and the first signal electrode to obtain a first optical phase modulation signal.

In step 1202, the optical modulator modulates the phase of the second optical carrier using the two electrical signals in the differential electrical signal to obtain a second optical phase modulation signal.

The light modulator includes a first signal electrode and a second signal electrode. The second signal electrode is used to connect the other end of the differential electrical signal. A second waveguide is included between the first signal electrode and the second signal electrode. The second waveguide is used to transmit the second optical carrier. The optical modulator modulates the other of the two optical carriers through the first signal electrode and the second signal electrode to obtain a second optical phase modulation signal.

In step 1203, the optical modulator interferes with the first optical phase modulation signal and the second optical phase modulation signal to obtain a modulated optical signal.

The optical modulator includes a beam combiner. The optical modulator interferes the first optical phase modulation signal and the second optical phase modulation signal through the beam combiner to obtain a modulated optical signal.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in the present application, and all of them should be covered. within the protection scope of this application.

Claims

An optical modulator, characterized in that it comprises a beam splitter, a first ground electrode, a first waveguide, a first signal electrode, a second waveguide, a second signal electrode and a beam combiner, wherein:

The output end of the beam splitter is connected to the input ends of the first waveguide and the second waveguide, and the input end of the beam combiner is connected to the output ends of the first waveguide and the second waveguide;

The first signal electrode is located between the first waveguide and the second waveguide;

The first waveguide is located between the first ground electrode and the first signal electrode;

The second waveguide is located between the first signal electrode and the second signal electrode.
The optical modulator according to claim 1, wherein the first ground electrode and the second signal electrode are symmetrically distributed with the first signal electrode as the center.
The optical modulator according to claim 1 or 2, characterized in that the optical modulator further includes a second ground electrode, and the second signal electrode is located between the second ground electrode and the second waveguide. .
The optical modulator according to claim 3, wherein the second ground electrode and the first ground electrode are symmetrically distributed around the second waveguide.
The optical modulator according to claim 3 or 4, characterized in that the optical modulator further includes a first dummy waveguide, the first dummy waveguide is located between the second ground electrode and the second signal electrode. between.
The optical modulator according to claim 5, wherein the first waveguide and the first pseudo waveguide are symmetrically distributed with the second waveguide as the center.
The light modulator according to any one of claims 3 to 6, characterized in that the light modulator further includes an electrical connection structure for connecting the second ground electrode and the third ground electrode. A grounding electrode.
The light modulator according to claim 7, characterized in that the electrical connection structure is a plurality of connection lines, and the distance between any two adjacent connection lines among the plurality of connection lines is 100 to 500 microns. between.
The light modulator according to any one of claims 3 to 8, characterized in that the light modulator further includes a first resistor and a second resistor, wherein:

The first resistor is connected to the output end of the first signal electrode;

The second resistor is connected to the output end of the second signal electrode.
The optical modulator according to claim 9, characterized in that the optical modulator further includes a first capacitor and a second capacitor, wherein:

The first capacitor is connected to the input end of the first signal electrode;

The second capacitor is connected to the input end of the second signal electrode;

The first resistor and the second resistor are connected to a DC bias voltage.
The light modulator according to claim 9, characterized in that:

The first resistor and the second resistor are connected to a ground wire;

The first ground electrode and the second ground electrode are connected to a DC bias voltage.
The light modulator according to any one of claims 3 to 11, characterized in that the light modulator has a U-shaped structure, and the U-shaped structure includes a first linear part, a curved part and a third connected in sequence. 2 straight parts;

The first waveguide being located between the first ground electrode and the first signal electrode comprises: in the first straight portion, the first waveguide being located between the first ground electrode and the first signal electrode;

The second waveguide is located between the first signal electrode and the second signal electrode, including: in the first linear portion, the second waveguide is located between the first signal electrode and the second signal electrode. between electrodes;

In the second linear portion, the first waveguide is located between the first signal electrode and the second signal electrode, and the second waveguide is located between the second signal electrode and the second ground electrode. between.
The optical modulator according to claim 12, characterized in that the optical modulator further includes a second false waveguide, wherein: in the second linear portion, the second false waveguide is located at the first ground electrode. and between the first signal electrode.
An optical module, characterized by comprising a laser and the optical modulator according to any one of claims 1 to 13, wherein:

The laser is used to output an optical carrier wave to the optical modulator;

The optical modulator is used to modulate the optical carrier and output a modulated optical signal.
An optical sending device, characterized by comprising a processor and an optical module as claimed in claim 14, wherein:

The processor is configured to output differential electrical signals to the optical module;

The optical module is used to modulate an optical carrier according to the differential electrical signal and output a modulated optical signal.
An optical communication system, characterized by comprising an optical receiving device and an optical sending device as claimed in claim 15, wherein:

The optical sending device is configured to send a modulated optical signal to the optical receiving device;

The optical receiving device is used to demodulate the modulated optical signal to obtain an electrical signal.
A modulation method, characterized by including:

Modulate the phase of the first optical carrier by one of the electrical signals in the differential electrical signal to obtain the first optical phase modulation signal;

The phase of the second optical carrier is modulated by the two electrical signals in the differential electrical signal to obtain a second optical phase modulation signal;

The first optical phase modulation signal and the second optical phase modulation signal are interfered to obtain a modulated optical signal.